An electric mechanical watch uses a motor driven by the electric power to actuate physical hands on a clock to indicate time information. The electrical mechanical watch keeps the hand design basically as the same as a mechanical watch, which is a sign of good taste. However, the electrical mechanical watch is much cheaper, thereby becoming a mainstream in the watch market. The time adjusting approach used in conventional electric mechanical watches is to rotate crowns so as to actuate the hands and thus change their positions. However, for a complex watch, there are many indicators (or hands) on a dial and the number of the crowns has to be increased correspondingly. Therefore, as to a wristwatch having a complex dial, not only the difficulty in designing a mechanism for the time adjustment is increased, but also it is very inconvenient for a user to adjust the time by using a great amount of crowns.